Machine gun and other automatic firearm



Aug. 19, 1930. c. soNclNr 1,773,441'

I MACHINE GUN AND OTHER AUTOMATIC FIRERM Filed Abril 11,. 192s 2 sheets-sheet 1 zo Y Jy M W am Aug. 19,l 1930.l c. soNclNl 1,773,441

I MACHINE-5.' GN AND OTHER AUTOMATIC FIREARM l 2Filed April 11, 1928 2 sheets-sheer 2 Patented Aug. 19,1930

'UNITED STATES PATENT OFFICE CESARE SONCINI, OF BRESCIA, ITALY, ASSIGNOR TO SOCIET ITALIANA ERNESTO BREDA PER COSTRUZIONI MECCANICHE, OF MILAN, ITALY MACHINE GUN .AND .OTHER AUTOMATIC FIREARM Application med April 11,

This invention relates to vautomatic machine guns and firearms of the kind in which the operations of the mechanism are automatically effected by the energy of recoil of moving parts, and in which a lever is provided for amplifying such recoil motion for parts of the said mechanism.

. According'to the invention, an automatic machine gun or firearmy of the kind referred to is characterized in' that the amplifying lever is located in the upper part of the breech casing and is bifurcated, the two prongs thereof acting symmetricallv on the head of the breech-bolt on either side 0f the axis of the gun or firearm.

The said amplifying lever and the movable breech-frame carrying the barrel are also designed to be connected together-for insgince, by hook means-during the movement of the lever to thrust back the breechbolt, so that 'the frame is held during such movement notwithstanding inclination of the firearm. Two reaction or return springs are employed to absorb the energy of recoll and are disposed symmetrically and parallel with respect to the vertical plane passing through the axis ofthe firearm and act in parallel guides on two connected members slidable in said guides and provided at their median part y 3Q with a projection extending to the axis of the gun so as to bear against the rear end of the breech-bolt, screw means being provided for adjusting the said connected members with relation to the said projection.

The locking of the breech-bolt in closed position is effected by a member moving with the barrel in its recoil and return movements,

'the said member being disposed in the median part of the firearm symmetrically with respect to the axis thereof and capable of sliding vertically with respect to the said axis by means of inclined guides arranged on the two lateral walls of the breech-casing of the gun. l In order that the invention may be fully understood, reference will be made to the accompanying drawing, in which: y

Figure 1 is a longitudinal section of a ma- 'X chine gun constructed in accordance with the inventionand showing the breech open;

Fig. 2 is a cross-section on line 2-2, Fig. 1;

1928. Serial No. 269,227.

Fig. 3 is a view similar to Fig. 2 but showing a dierent position of the parts;

Fig. 4 is a cross-section on line 4 4, Fig. l; Fig. 5 is a sectional side view of a detail drawn to an enlarged scale;

gig. 6 is a view at right angles to Fig. 5; an

Fig. 7 is a view similar to Fig. l of a portion of the mechanism indicated therein, but showing` the breech closed. Referring to the drawing, l is a breechcasing closed at its forward end by a front cover' 2 to which is screwed a barrel-bearing socket 3; the casing being closed at its rear end by a handle 4 sliding inf-suitable vertical guides. In the side, upper and lower members of the breech-casing are openings in which are arranged devices, some of which play an important part in the motion of the parts of the weapon, while others are merely of a protective nature. The latter devices comprise the side plates 5, the upper plates 6 and 7, and the sheath or cover 8 for the reaction or return springs, the lower plate 9 c0ntaining the trigger-group and feed-box, and the hinged casing 10 enclosing the mechanism 11 for hand-feed of the cartridges.

Almost all these members have an importantfunction and must be made with particular care and of special materials; it is, however, important that they should be simply applied on the' weapon, as this allows the breech-casingl to be reduced to a` piece which,

as it forms solelyv the frame of the outside members, can be made in ordinary soft steel, thereby greatly simplifying its manufacture.

The casing of the weapon, notwithstanding its being of rectangular section toward its front end, can be easily machined and true'd by the usual inside grinding 1, .achines through the openings'above referred to.

The members which effect the closing of the firing chamber'during the explosion of the cartridges are all arranged in the front .i

cavity of the casing, and their special feature is their symmetrical and central arrangement with regard to the axis of the weapon, both in shape and position, as well as in operation.

The barrel 12 is screwed atits breech end.,

to the breech-frame y13 by means of aV square thread which secures perfect contact of the parts longitudinally, while allowing suitable radial play between the barrel and the breech-frame in order to compensate for lateral deformations of the barrel caused by the overheating of the same during continuous fire. This frame 13 slides along the casing with the barrel and the locking block 14l therefor arranged inside the said frame, the said block being caused to slide vertically by the engagement of slots 15 therein with 1nclined guides 15- formed on the two side plates 5.

The breech-bolt 16 slides in the casing, and its head 17 engages with, and is held by, the locking block 14 during the firing of each cartridge, as indicated in Fig. 7. The recoil or return device comprises two upper mem-y bers slidably arranged in two chambers 18 in the cover or sheath 8, which chambers also enclose and guide two recoil-operated reaction or return springs 8a arranged in chambe'rs 18 and acting on said members; the said springs being disposedsymmetrically and parallel with respect to the vertical plane passing through the axis of the gun. A central chamber 19 is also provided in sheath 8 between the outer chambers 18 and houses the median part 20 of the recoil device. which part 2O connects the two previouslv-mentioned members of said device and extends to the axis of the gun; the compression of said springs being effected bv meansl of part 2O which, during the recoil phase, is pushed backward bv the rear end, of breech-bolt 16. The compression of the two springs 8a can be regulated bv a threaded adjusting rod 21 which. on being rotated. moves endwise a sleeve 22 forming a portion of part 20 and rocked therein by the thrust which it receives from a projection or lug 27 on the breechframe 13 against which it bears (Fig. 1). During this rocking movement, the lower ends 25'b of the arms of lever 25 strike against the head of the bolt on either side of the axis thereof and transmit to the bolt an amplifying recoil action; and in order to prevent said lever and, consequently, the breech-frame 13 connected thereto, from returning to closed position shown in Fig. 7 before the bolt has completed its full forward stroke, a plunger 28 lis employed which is normally pressed downward by a spring 28" and is provided with a catch or hook 25" for coaction with a cross-piece 25 on lever 25.

rlhe plunger 28 is so arranged as to engage said lever at the. instant of the opening operation; its catch 25 hooking over the crosspiece 25 (Fig. 5) and thereby holding the lever in the position illustrated. Finally, the lever is provided with a pair of wings or grippers 29 which engage in grooves 29 in the projection 27 on the breech-frame 18 and thus hold said frame during the entire opening operation, regardless of the angle at which the/weapon is being fired.

Owing to the arrangement described, plunger 28 is always pushed downward by spring 28, so that during the opening motion the cross-piece 25 of the amplifying lever 25 rides under and lifts catch 25 and thus forces said plunger upward, whereupon the hook end of the catch snaps over the crosspiece and locks the lever in theposition shown. When the bolt returns to closed position, it-slides lightly past the beveled face 28 of the plunger and cams it upward, so that catch 25" is thereby disengaged from cross-piece 25. The whole mechanism thereupon returns to the position of rest and complete closure illustrated in Fig. 7.

lt is to be noted that all the members of the amplifying mechanism can readily be taken apart, so that their replacement is very easy and can be effected independently of the general dismantling of the weapon. Furthermore, the amplifying lever 25 is so 100 formed and so arranged in the locking group as to exert its action symmetrically against the head of the bolt with respect to the axis of motion. f v

I claim as my invention 1. In an automatic firearm, a breech-casing, a breech-bolt movable endwise therein and provided with a head, and an automatically-operating, forked amplifying lever in the upper part of said casing, the two arms 110 of the fork acting symmetrically on the bolt head on either side of the axis of the weapon.

2. 1n an automatic firearm, a breech-cas ing, a breech-frame movable therein, a breech-bolt, and an amplifying lever acting 115 on the bolt head and having a hook with which said frame engages during the movement of the lever to retract the bolt, whereby the frame is held during such movement regardless of the inclination of the weapon. 12o

3. A11 automatic rearm, comprisin a, breech-casing, a recoil-operated breech-bolt movable therein, a return device guided'for endwise sliding movement in the casing and having a projection extending toward the 125 axis of the weapon to support the adjacent end of the bolt, and reaction spring means acting on said return device to oppose the recoil movement of said bolt; said return device comprising two long parallel members x30 connected by said projection and slidably fitted in parallel guides; and said reaction spring means comprising two separate springs likewise itting.,lr in said guides and being disposed symmetrically and parallel with respect to the vertical plane that passes through the axis of the Weapon.

4. An automatic irearm according to claim 3, in which a threaded rod is provided for moving said connected parallel members re1- atively to said projection and thereby adjusting the pressure of the reaction springs.

In testimony whereof I aflix my signature.

CESARE SONCINI. 

